‘Argo’

"Thriller" has become a lazy genre label for films that too often prove to be as thrilling as compost and twice as smelly.

But a film that mixes searing international politics, crackling performances and a pulse-pounding escape scene that stretches out for a full half-hour?

That's a thriller. That's "Argo."

And look who's delivering the knockout: Ben Affleck, a guy once written off as a lightweight Hollywood dilettante who has somehow reinvented himself as one of our finest directors.

Working from a terrific screenplay by Chris Terrio, Affleck rolls out an engrossing story that not only illuminates a little-known subplot to an indelible episode in American history but also plugs directly into our current geopolitics.

The backdrop is the 1979 storming of the U.S. Embassy in Tehran by Iranian militants who took 52 Americans hostage.

The broad strokes of the 444-day crisis are hauntingly familiar. But there's another side to that story, unknown outside government channels until details were declassified in 1997 and still not well known today: Six Americans made it out of the embassy — slipping the militants only because they worked in the visa office, the one part of the compound with direct access to the streets of Tehran.

They took refuge in the official residence of then-Canadian Ambassador Ken Taylor (Victor Garber) — and the U.S. had another big problem on its hands.

After Mendez listens to CIA staffers discuss one stupid rescue plan after another, an idea hits while he's home watching "Battle for the Planet of the Apes": Build covers for the six refugees as a Canadian film crew scouting locations in Iran for a cheesy "Star Wars" rip-off called "Argo." And Mendez, the "director" of this classic, will then escort them out.

"This is the best bad idea we have, by far," Mendez's boss, Jack O'Donnell (Bryan Cranston), tells the dubious higher-ups.

But to have any chance of success, Mendez must convince the world that an actual movie is being made, since the Iranian authorities certainly will try to verify the whole deal.

He enlists old friend John Chambers (John Goodman), a makeup artist who has done side work for the Agency in the past, who in turn signs up veteran producer Lester Siegel (Alan Arkin at his Alan Arkin-est), a classic Hollywood BS artist with a keen appreciation for the project's ample surrealism.

And he's totally up for it: "If I'm gonna make a fake movie, it's gonna be a fake hit!" he exults.

Affleck and Torrio also show an appreciation for the ironic contrasts between the worlds of clandestine spy-craft and Hollywood showmanship — mega-weird in vastly different ways — as reflected in the insiders' joking mantra for the operation: "Argo f--- yourself."

The setup is taut and tense, but the film hits a whole new gear when the op goes into motion.

Mendez must get the six refugees (the most recognizable faces are Tate Donovan and Clea DuVall) out of the Canadian compound in a vintage Volkswagen bus, crawl through tight streets filled with angry protesters, then get past multiple rings of airport security to reach their Swissair flight — all the while hoping the boys back at Langley haven't screwed up their reservations.

And just for added incentive, the militants have painstakingly reconstructed shredded embassy documents and just realized that six U.S. staffers are AWOL.

No car chases, gunfights or fisticuffs, but the tension in this long scene, with life and death in the balance every second, is thick enough to thwart a chainsaw.

If there's a flaw, it's that the back story crafted around Mendez — he's a bit of a lost soul, estranged from his wife and son — feels undernourished.

But that quibble aside, "Argo" is an amazing story about a decent guy who did a great thing, risking his own life on a long gamble and pulling it off — not for money, fame or glory, but because it was the right thing to do.

No wonder the packed house at my screening exploded into a thunderous ovation at the end.